This NICHD Ruth L. Kirschstein National Research Service Award application seeks to train pre-doctoral students in reproductive, perinatal, and pediatric epidemiology. This field has experienced slower growth relative to other fields in epidemiology, despite a clear public health need. The long-term objective of this application is to expand the field of reproductive, perinatal, and pediatric epidemiology through increased investigator-initiated research by solidly trained scientists and to ultimately reduce the population burden of reproductive and pediatric diseases. Didactic and applied training will be provided by three Boston University School of Public Health centers: the Slone Epidemiology Center, the Epidemiology Department, and the Maternal and Child Health Department. Through these three centers, trainees will: 1) gain a solid understanding of theoretical and applied epidemiology and associated biostatistics, 2) learn the basic biological processes of and major clinical features of pregnancy and/or childhood, 3) contribute to a research project under the guidance of a program mentor, and 4) learn to write bio-medical manuscripts and grant proposals, and 5) demonstrate the ability to conduct independent, original research. The three centers within Boston University School of Public Health are ideally suited to meet these objectives. Major strengths of the program include 1) easy incorporation into an established, accredited epidemiology doctoral program that attracts high level students;2) established course curricula in relevant topics;3) an abundance of reproductive, perinatal, and pediatric research resources;and 4) faculty mentors with expertise in epidemiologic methods and applied epidemiology in reproductive, perinatal, and pediatric outcomes and pharmacologies, environmental exposures, infectious disease, social/behavioral factors such as illicit drug use, and racial/ethnic disparities;and 5) faculty mentors with track records in training academic reproductive, pediatric, and perinatal epidemiologists. The program will be overseen by a director who is a recognized reproductive epidemiologist and whose commitment to the field and links to the classroom, research, and mentoring components of all three centers, ensure a successful training program.